Synthesis and electronic structure of nitrogen-doped graphene

The crystalline and electronic structure of nitrogen-doped graphene (N-graphene) has been studied by photoelectron spectroscopy and scanning tunneling microscopy. Synthesis of N-graphene from triazine molecules on Ni(111) surface results in incorporation into graphene of nitrogen atoms primarily in the pyridinic configuration. It has been found that inclusions of nitrogen enhance significantly thermal stability of graphene on nickel. An analysis of the electronic structure of N-graphene intercalated by gold atoms has revealed that the pyridinic nitrogen culminates in weak $p$-type doping, in full agreement with theoretical predictions. Subsequent thermal treatment makes possible conversion of the major part of nitrogen atoms into the substitutional configuration, which involves $n$-type doping. It has been shown that the crystalline structure of the N graphene thus obtained reveals local distortions presumably caused by inhomogeneous distribution of impurities in the layer. The results obtained have demonstrated a promising application potential of this approach for development of electronic devices based on graphene with controllable type of conduction and carrier concentration.